We will publish AtCoder Library (ACL). This is a collection of implementation of various algorithms written by us. You can use it on most of our contests. https://img.atcoder.jp/practice2/ac-library.zip Please refer to the document inside the zip file for details. Also, please try to use it in the following practice contest: https://atcoder.jp/contests/practice2 We will hold two contests on 20th and 26th, September, to celebrate this: - https://atcoder.jp/contests/acl1 - https://atcoder.jp/contests/acl2 Many problems (but not necessarily all) in these contests will be related to ACL.